CVE-2025-20160: cisco cisco ios xe software Improper Authentication

Vulnerability summary

CVE-2025-20160 is a high (CVSS 8.1) Improper Authentication vulnerability in cisco cisco ios xe software. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 36.4% of scored vulnerabilities.

Timeline

1. 24-09-2025
   PublishedVulnerability first disclosed.
2. 26-02-2026
   Last modifiedVulnerability information updated.

Description

A vulnerability in the implementation of the TACACS+ protocol in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to view sensitive data or bypass authentication. This vulnerability exists because the system does not properly check whether the required TACACS+ shared secret is configured. A machine-in-the-middle attacker could exploit this vulnerability by intercepting and reading unencrypted TACACS+ messages or impersonating the TACACS+ server and falsely accepting arbitrary authentication requests. A successful exploit could allow the attacker to view sensitive information in a TACACS+ message or bypass authentication and gain access to the affected device.

• CWE-287Improper AuthenticationWhen an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.